Low GH and KH, high PH... what should I do?

[Trumpee]

I have just set up a new tank and am ready to start cycling it but I'm experiencing a water chemistry challenge. I have well water with a commercial grade softener for my house. Testing the GH, KH, and Ph here are the results:

Water after passing through softener:
GH <= 1 degree/17.9 ppm
KH <= 1 degree/17.9 ppm
Ph = 7.9 – 8.0

Water before passing through softener:
GH <= 7 degree/125.3 ppm
KH <= 1 degree/17.9 ppm
Ph = 7.9 – 8.0

I've been using a neutral regulator from SeaChem to try and stabilize the Ph at 7.0 but after several doses over 5 days, it’s come down only a few points, seeming to resist the change. I understand this Ph change resistance is usually due to a high KH providing that stability. However, my KH is measuring extremely low. I'm hoping someone might be able to help me make sense of this. I would prefer not to have to mess with Ph constantly (cost and time) rather provide a stable environment without chemicals (healthier for the fish). Thinking ahead as well, when I do water changes, If I can’t get the new water Ph down immediately to equal that of the Ph in the tank, I’m afraid the water addition will increase the tank Ph too much, too quickly and be harmful to the fish.

I’m planning to build a community tank 7.9 - 8.0 for a general community tank does sound a bit high from everything I have read.

Questions:
If the KH is so low, why would the Ph be so resistant to change?

Lastly, what recommendations do you have? Get the Ph down and KH up? If so, how? And how would I get the Ph down quickly with water changes before adding to the tank? Or, perhaps get away from the community tank idea and build a tank that does better with higher Ph water?

Thanks.

 

[rkilling1]

First, most community type fish will do just fine with a pH of 8.0.

Secondly, something is wrong with your tests or chemicals in your water. Having 1 degree for your KH should put your pH aroung 7.0 not 8.0.

Have you tried testing your tap water after it sits in a cup for 24 hours? This will drive off any gases within it.

Is there a way to use the water prior to going into the softner?

If it comes down to needing to increase the KH, all you have to do is purchase some baking soda. There are plenty of websites that have calculations for adding it.

I would steer clear of any pH regulators. Having a stable pH far outweighs having an ideal one.

 

[jsoong]

First, I would suggest using water before the softener, the softener exchanges K or Na for the Ca/Mg that was in the water at a 2 to 1 ratio. The fish actually see an INCREASED osmotic load (not decrease as you might expect with softened water). Plus, if you keep inverts or plants you need the Ca & Mg.

Assuming that your tests are correct, a low KH coupled with high pH means that you have a buffer other than CO3/HCO3 in your water. FAIK, home KH test only measure the carbonates & nothing else. The 2nd buffer is keeping your pH high and it will be difficult to alter the pH with any added pH adjuster (which is basically just another buffer.)

Depending on what your other buffer is, you might or might not have trouble using your water ....eg. if the buffer happens to be NO3 or PO4, you might have major algae outbreak. For people with REALLY bad water, they use a reverse-osmosis unit to remove ALL the ions from the water, then add back an appropriate amount of NaHCO3 (baking soda) or CaCO3 (crush shells, coral) to maintain pH stability ... <or a commercial mix for chilid, or salt mix for SW/brackish.>

I would suggest talking to your lfs to see how fish do in local water before doing major messing with the chemistry. Your well water would have been tested before you drink it, that result might give a clue as well.